Electric coil.



No. 736,319. .PATENTED AUG. 11, 1903.

R. VARLEY. I

ELECTRIC COIL.

APPLICATION FILED MAY 2, 1903.

WWI/1W mwwtm/ Patented August 11, 1903.

UNITED STATES- PATENT OFFICE.

RICHARD VARLEY, OF PROVIDENCE, RHODE ISLAND, ASSIGNOR TO VARLEY DUPLEXMAGNET COMPANY, A CORPORATION OF NEW JERSEY.

ELECTRIC COIL.

SPECIFICATION forming part of Letters Patent No. 736,319, dated August11, 1903.

Application filed May 2, 1903. Serial No.155,417.' (N0 model.)

T0 at 1071,0771, it may concern:

Be it known that I, RICHARD VARLEY,a citizen of the United States,residing at Providence, in the county of Providence and State of RhodeIsland, have invented certain new and useful Improvements in ElectricCoils, of which the following is a full, clear and exact description. A

My invention relates to electrical coils, such as are commonly known assparking-coils.

The object of the invention is to provide a construction whereby thecoil will be waterproof and in which the wooden heads commonly used toprotect the ends of the coil will be firmly secured in place andprevented from becoming detached.

A further object is to produce a cheap form of construction.

In the accompanying drawings, Figure l is a side elevation with partsbroken away to show a section of the coil, and Fig. 2 a face view of oneof the heads.

a indicates the coil-winding, and b the usual core, consisting of abunch of iron wires. The core, as usual, projects a short distancebeyond the heads of the coil.

0 and 0 indicate two end pieces or heads of insulating material,commonly of wood, and used to protect the ends of the coils as well asto carry binding-posts, one of which is shown at (I. These heads asusually applied to the coil have a central orifice 6, into which theprojecting end of the core fits. To give rigidity to the bunchedwire-coil, itis common to inclose it in a pasteboard tube I), whichextends the full length of the core and adds its strength to theprojecting ends. The winding is commonly surrounded by a sleeve ofpasteboard f, which butts up against the face of the heads whenassembled. The head is usually secured in place by inserting theprojecting end of the core in the central orifice and gluing all of theabutting surfaces together. It will be seen that lateral pressures orblows directed against the sides of the head will tend to break it loosefrom the central core. For. this reason it has been customary to makethe tube surround in g the core thicker than is otherwise required toresist these lateral blows.

In accordance with my improved manner of constructing the coil I form adeep annu lar groove 6 in the face of the head near its edge and extendthe outer sleeve f, so that it will enter said groove at the same timethat the core enters the central orifice. By using glue in the annulargroove as well as between all of the abutting-faces I produce a verysolid connection for the head, which is capable of resisting the lateralforces above referred to much better than the old construction. By thisconstruction it is also possible to make the diameter of the outersleeve f somewhat greater than the diameter of the coil and provide anannular space g for waterproofing waX. The groove 6 centers the sleevearound the coil, so' that after one head and the sleeve have beenapplied to the coil the wax in liquid state can be poured in and thesecond head applied. The war; thus ap- 7o plied permeates the pores andcavities in the adjoining parts and effectually bars the entranceofmoisture to the windings of the coil.

Another advantage flows from the method of securing the heads devised byme in that it is possible to use a much thinner tube around thebunched-wire core, the thickness required being only such as to resistthe tension of the winding, or, in case the core is slipped into placeafter the coil is wound, the tube can be merely thick enough tohold thebunched wires in place. The advantage gained by a thin tube is that itpermits of the same number of turns or convolutions in the winding withless length of wire, each turn being of less diameter than those in theold form.

Having described my invention, '1 claim An electrical coil having a coreand a surrounding sleeve of greater diameter than the coil, both ofwhich project beyond the ends of the coil, in combination with headsprovided with a central aperture and an annular concentric groove intowhich the projecting core and sleeve respectively extend, and a body ofwax filling the annular space between the sleeve and coil, substantiallyas described.

In witness whereof I subscribe my signature in presence of twowitnesses.

RICHARD VARLEY. Witnesses:

WM. A. RosENBAUM, WALDo M. CHA'PIN.

